Interactions between natural enemies and pollinators: combining ecological theory with agroecological management

Abstract

Interspecific interactions are major drivers shaping ecological communities. Nevertheless, understanding how and to what extent they affect ecosystem functioning remains a key challenge for both fundamental and applied ecology. In the context of agricultural biodiversity loss, sustaining populations of organisms that provide essential ecosystem services is crucial but remains challenging. Interactions among beneficial organisms may explain such results, as they impact organisms' fitness. These effects could accumulate when scaled up to the population level, modifying community structure and functioning. Interactions could also affect organisms' foraging behaviour and consequently their efficiency. Here, we review and synthesize the knowledge of the effect of interactions within and between two groups of ecosystem services providers: natural enemies and pollinators, respectively providing biological control of pests and crop pollination services. We show that intra-guild predation, competition and resource partitioning are common interactions structuring natural enemy communities, and may affect their effectiveness to control pests. Nevertheless, actual evidence in complex systems and long-term studies are still missing, and application in agricultural settings is only at its beginning. Similarly, competition and resource partitioning among pollinators is a recent focus of ecological research. Studying facilitative interactions is clearly missing. Finally, while we show that interactions between natural enemies and pollinators can theoretically happen in natura due to the use of similar resources and habitats, this question remains poorly addressed. We discuss future research perspectives to better capture the complexity of biodiversity effects on ecosystem functioning, and propose guidelines to the implementation of more efficient multi-service schemes in agroecological landscapes.

Complex Effects of a Land-Use Gradient on Pollinators and Natural Enemies: Natural Habitats Mitigate the Effects of Aphid Infestation on Pollination Services

“…However, recognizing that these groups may influence each other is essential, as such interactions would significantly impact their effectiveness in providing ecosystem services [7]. Therefore, there is a growing interest in understanding these interactions under real-world field conditions and their effects on plant production and crop yield, although studies on this topic remain limited [8].…”

“…The interactions between co-occurring pollinators and natural enemies can result in positive, negative, or neutral effects on ecosystem service delivery depending on underlying mechanisms [8,9]. Positive (synergistic) interactions may boost plant productivity, with natural enemies indirectly benefiting pollinators by controlling pests, contributing to increased visit rewards and availability of flowers, especially when dealing with florivorous pests [10,11].…”

“…A comprehensive approach is necessary to understand the mechanisms behind pollination and pest control service delivery and to develop integrated pest and pollinator management strategies [7,26]. Nonetheless, studying multi-guild interactions across diverse landscapes and habitats remains challenging [8], including the integration of data collected through various methods that are suitable for studying different organisms within the system. In our study, conducted in a Mediterranean agro-ecosystem along a land-use gradient, we used phytometer plants to simultaneously observe pollinator activity, aphid predation, parasitism rates, and fruit and seed set.…”